vendor snappy

cc @andybons @petermattis @spencerkimball @tschottdorf 
yeah. autotools et al are THE worst. I went on a facebook rant and my friend recommended http://www.amazon.co.uk/Die-GNU-Autotools-Leitfaden-Softwaredistribution/dp/3936546487

I wanted to vendor it but not patch the autogen.sh because that makes pulling updates to submodules a little more involved.